On effects of stage of lactation and subclinical mastitis on milk quality in goats

1. On effects of stage of lactation and subclinical mastitis on milk quality in goats

2. Nissim Silanikove Biology of Lactation Lab, Agricultural Research Organization, The Volcani Center, Israel Uzi Merin Department of Food Science, Agricultural Research Organization, The Volcani Center, Israel Gabriel Leitner KimronVeterinary Institute, Israel

3. Milk quality: fat, total proteins, casein, curd and are affected by intramammaryInfection and stage of lactation Cheese quality: yield, structure, smell, flavor, shelf life and all these factors are subjected to the effect of intramammary Infection and stage of lactation

4. Traditional farming • Along the lactation different • products are produced • 2. Milk from clinically infected glands is discarded • Modern dairy forming • Animals are milked while at • different stages of lactation • 2. A large number of glands are infected with a variety of bacteria

5. Animal model built on the gland level One udder-half identified with CNS species and the contra-lateral being free of bacteria S. caprae S. chromogenes S. epidermidis S. simulans S. xylosus - +

6. + -

7. Milk yield (half) of sheep or goat infected with CNS specie in one gland and the contra-lateral being free.Open bars – S; Hatched bars – G

8. Cork 2005 Curd firmness (volts) Clotting time (sec) 1 2 3

9. Curd yield and clotting time of goat milk from infected vs. uninfected udder-halves Uninfected Infected

10. Milk yield and SCC along the lactation of uninfected glands 1000 3.5 SCC (1000) Milk K/day 100 0.5 Day in milk

11. Milk yield and SCC along the lactation of infected glands 1000 3.5 SCC (x 1000) Milk (K/day) 100 0.5 Days in milk

12. Days in milk (DIM), milk yield, SCC, gross milk composition (fat, protein, casein, lactose) , rennet clotting time (RCT) and curd firmness (CF) of goats’ milk for mid-lactation, bacteria-free (MLG-F), mid-lactating, infected (MLG-I), and late-lactation, bacteria-free (LLG)a.

13. * Many of the animals with subclinical chronic infection are not noted because there are no recognizable symptoms and the milk appearance is normal * End of lactation goats show increased SCC regardless of IMI ** Routine milk testing such as CMT on the animal side or more advanced techniques like the sophisticated cell counters allow the identification of subclinically infected animals close to the occurrence of the infection. However, it is laborious and/or require special equipment to perform *** On-line computerized milking systems are designed in part to overcome these conditions and to apply genuine real-time data acquisition on individual animals, including milk yield and conductivity

14. CASEINOLYSIS INDEX Infected gland ~ 3,000,000 Cell depended Healthy gland ~ 50,000 Cows ~ 300,000 goats and sheep Bacteria and Cells depended

15. Log SCC and Cf of curd of goat milk at mid lactation with and without IMI and at the end of lactation without IMI- SCC is not the best predicting variable for milk quality Low quality curd Log SCC correlation ( r= -0.4( Curd firmness (Cf)

16. Clotting time and curd firmness

18. Healthy Infected Staph. chromogenes Strep. dysgalactiae

19. Correlations and respective probability (P[r]) for cows, goats, and)sheep between levels of protein, casein, (protein + fat), % casein and lactose, • SCC, and log SCC, and curd firmness (CF) of milk: • ∗ – P > 0.001; ∗∗ – P > 0.05; NS – not significant

20. % lactose and Cf of curd of goat milk at mid lactation with and without IMI and at the end of lactation without IMI Low quality curd % Lactose Lactose lower than 4% Curd firmness (Cf)

21. Influence of percent lactose in milk on curd firmness as measured by the Optigraph

22. * It was found that lactose content in milk is the best indicator for milk quality for cheese making. * It is already implemented in Afilab(KibutzAfikim, Israel) On- line FTIR-based recording system in dairy cows milking parlors The system enables to separate on-line milk unfit for cheese making from milk suitable for cheese on the pipe-line between the milking parlor and the tank during milking and store them in separate tanks * Feasibility test of the system for small ruminants was conducted The system will enable direct and cheap daily identification of animals with milk unsuitable for cheese making and perhaps to separate it as already done with cows

23. Plasmin activity: sheep or goat with one gland infected with CNS specie and the contra-lateral being free Sheep + 195%, P < 0.0003 Goat + 73%, P < 0.0007 PL activity, units/mL

24. 52 35 28 2114 0% 0% 50% 50% 100% 100% SDS PAGE Tricine

25. Amounts of p–p and FE obtained from milk samples. Numbers in parenthesis indicate the number of glands tested. Proteose peptone determined using the Bradford (1976) method, FE estimated as the area under the OD280 values of the FPLC chromatogram; values are given as mean and SD in mg L−1.

26.  Dose–response effect of the addition of fraction E (FE) from milk obtained from healthy glands (open bars) and from Str. dysgalactiae-infected glands (hatched bars) to milk from healthy glands on rennet clotting time and curd firmness, as assessed using the Optigraph.

27. The effect of addition of up to 5 mg fraction E (FE) to 10 mL of milk obtained from healthy or Str. dysgalactiae-infected glands, in the presence of calcium ions, to milk from healthy glands, on rennet clotting time (RCT) and curd firmness (CF), as assessed using the Optigraph.

28. Anti-Lactogenic hormones e.g., Cortisol, Estrogen Lactogenic hormones e.g., GH, Prolactin Blood alveoli PA Reaction type 2 Reaction type 1 Lumen 1 2 PLG PL Frequent milking or suckling Milk stasis or bacterial invasion External effects: Milking, suckling, bacterial invasion

29. SCC is a good reference for milk quality if we compare good quality (300000 cell/ml) with low quality one (1 million cells and above). Milk for cheese production and caseinolysis are bacteria species-dependent and are poorly predicted by SCC SCC = somatic cell count PMN = polymorphonuclear Bacterial infection Activation of the innate system Cork 2005 Cellular response Oxidatiive response by NO-derived NO2 radical Cytokines, SCC (PMN) Plasmin Protein oxidation Caseinolysis Lipid oxidation

30. Effect of subclinical mastitis on oxidative, antioxidative and formation of oxidized substance in milk

32. subclinical mastitis is associated with significant losses in milk yield and quality for cheese production. Milk of subclinically infected glands is subjected to considerable NO-derived oxidative stress, which only moderately impose nitrosative stress on milk proteins. However, it is associated with significant loss of milk antioxidant capacity and vitamin C levels, which are particularly high in goats. Thus, it is concluded that subclinical mastitis induces unfavorable changes in milk quantity and composition, which affects considerably both to the farmers and the dairy sector that depend on goat’s milk.

33. Thanks, on behalf of the heroes!